1. Field of the Invention
This invention relates to an insulating bushing assembly for electrical devices such as distribution transformers.
2. Description of the Prior Art
Insulating bushings are used to mount an electrical conductor through a metal wall or cover of an electrical apparatus, such as a high voltage bushing on the cover of an electrical transformer. Examples of such bushings are disclosed in U.S. Pat. Nos. 1,010,592, 2,495,252, 2,953,628, 3,096,392, 3,116,362, and 3,278,833. In those patents the bushings are mounted in place by retaining means that have disadvantages including a multiplicity of parts as well as insufficient self-adjusting ability.
Associated with the foregoing has been the problem of large tolerance variations on finished porcelain bushings. Indeed, the large variation in tolerances has been the primary reason for attempts to compensate for the bushing size such as disclosed in the above listed patents. Bushings composed of epoxy resins are produced without any variations in tolerance, but epoxy resins are more costly than the more conventional materials.